As electronic devices become smaller and faster, their sensitivity to electrostatic charges is increased and electronic packaging has been provided to improve electrostatically dissipative properties. Electronics packaging is designed to prevent the build-up of static electrical charges and the consecutive electrostatic discharge (ESD) which can be responsible of serious damages to sensitive electronics and result in product defects and high scrap rates.
In order to ensure ESD protection, inherently electrically insulating polymers may be rendered conductive or dissipative by incorporating conductive fillers—such as carbon black (CB)—allowing effective dissipation of static electrical charges.
Currently conductive or dissipative plastics are dominated by CB, mainly because CB is relatively cheap in comparison to other conductive fillers, such as carbon fiber, carbon nanotubes (CNT), metal fiber, metal-coated carbon fiber, and metal powder. Addition level of CB must be sufficient so that particles create a conductive pathway through the materials. In consequence, high levels of CB (15-30%) are required to meet the requirements, which alter critical physical properties of the basic polymer such as impact strength, elongation and compound viscosity.
These properties need to be preserved when using other fillers instead of CB as conductive fillers. Nevertheless, a minimum concentration is required to obtain the desired conductivity. Since other fillers are more expensive than CB, there remains a need to provide improved conductive compositions which are electrically insulating and remain costly attractive.
Conductive compositions containing CNT are known. Production of polymer T-composites can be done by physically mixing the polymer powder and the CNT for example by shear mixing techniques or by grinding. However a disadvantage of these methods is that the CNT are not well dispersed in the polymer.